How does it feel?
Look for the finest quality green tea, perhaps a matcha blend, and in a cup pour on water just off the boil. The colour of the water will move from an immediate greenish-yellow to a darker yellow-brown. Do not add milk or whitener. After five minutes take a sip and note the familiar dry, refreshing taste, only subtly aromatic. If you take this in hot weather, you will also feel the cooling effect of even a hot cup of green tea.
Green tea is bitter, astringent, light and drying and safe to take regularly over many years.
What can I use it for?
Green tea is a healthy and refreshing daily drink that can be a good replacement for coffee, and may be better tolerated than black tea. There is some suggestion that it can be a useful part of a weight-loss regime.
For health problems it may best be seen as a long term health and wellbeing measure rather than a quick fix. It can be considered as a preventative against heart and circulatory disease, late-onset diabetes, dementia and even cancer. It is probably best value if you have high cholesterol levels, high blood pressure, and/or raised BMI (body-mass index).
Into the heart of Green Tea
Green tea, particularly its key ‘EGCG’ and other catechin constituents, have extraordinary antioxidant properties in the laboratory (stronger than vitamin C or E). However these are artificial environments and the real impact of antioxidants after consumption, digestion and metabolism in humans has been heavily over-promoted. Nevertheless the catechins in green tea appear to optimize the body’s own antioxidant defences, including via the ‘Nrf2 pathway’. This is likely to explain many of the health benefits of regular green tea consumption, particularly in reducing low-level inflammatory conditions. A very interesting area of benefit is in cases of ‘neuroinflammation’: recent observations that many brain and nervous problems may involve inflammation. A role here could justify the use of green tea, for example in chronic fatigue syndromes and to help prevent dementia.
A key part of the benefits of green tea are linked to its observed effects on improving the health and integrity of the lining of the blood vessels, the endothelium. It is at this surface that almost all inflammatory processes commence and ‘endothelial dysfunction’ has been implicated in a wide range of inflammatory diseases, cardiovascular problems, dementia and diabetes. Endothelial stresses may even contribute to the effects of ageing on the brain and nervous system.
Closely linked to this endothelial impact are likely benefits of green tea in reducing insulin resistance and improving glucose and fat metabolism. Modern lifestyles have dramatically increased insulin activity in the body, notably as a consequence of high carbohydrate diets and reduced exercise. Higher insulin levels eventually lead to endothelial and other cells becoming ‘insulin resistant’ with consequent disrupted sugar management and more fat storing. This ‘metabolic syndrome’ is associated with the onset of type 2 diabetes and associated cardiovascular problems, increased dementia risks and other long-term health consequences, and is perhaps the dominant health issue in modern developed societies.
Green tea is also a moderate source of caffeine. Caffeine in this context enhances cognitive alertness and helps to overcome fatigue and lift mood.
Green tea has been an important part of Chinese, and later Japanese and Korean social life over almost two millennia. The earliest accounts of Tea Ceremonies come from China around 1200 years ago during the Tang Dynasty when the ritual of infusing and serving tea was part of a religious ceremony called cha dao or ‘The Way of the Tea’.
Outside China tea was brought to Europe in the 16th century and became popular in Britain, with black tea overtaking green tea to become its most popular drink during the 18th century. It was initially promoted through ‘tea houses’ as a tonic and health drink before becoming a popular beverage. The British East India Company introduced tea production, as well as tea consumption, to India, in order to compete with the Chinese monopoly on tea.
What practitioners say
All the evidence and traditional usage points to the benefits of green tea being from drinking it regularly as part of a healthy lifestyle. This beverage habit, rather than supplements or practitioner prescriptions, is probably the most practicable option too. However the evidence points to some benefits being seen in only a few weeks and practitioners are likely to recommend drinking more green tea for the following purposes.
Brain performance: consumption of green tea, preferably as a life-long habit, is particularly helpful to reduce the effects of ageing and illness on cognitive function, memory retention and and other performance. The L-theanine in green tea increases serotonin, dopamine and gamma-aminobutyric acid (GABA) in the brain, all of which significantly boost mood, indicating it also in anxiety and depression.
Metabolic: green tea is recommended where there is a slow or under-active metabolic rate associated with higher BMI (body-mass index), belt size and other indicators of ‘metabolic syndrome’ all of which may point to late-onset diabetes and fatty liver problems.
Cardiovascular: The EGCG’s present in green tea protect the integrity of the blood vessels, so regular consumption is useful in any cardiovascular problem.
Skin: it has traditionally been used in inflammatory skin conditions associated with hormonal imbalance.
There is considerable evidence for the effects of long-term green tea intake in improving cognitive performance. In a major systematic review of the evidence (3), involving over 66,000 subjects, there were significant improvements in memory and cognition in those who drank one or more daily cups of green tea regularly.
Given the likely role of endothelial dysfunction in the origins of inflammatory processes, cardiovascular problems, and ageing, it is noteworthy that there are clinical studies (4,5) that reinforce the laboratory observations that green tea does improve endothelial function, with wider benefits on the cardiovascular system (6).
It is also interesting to note that regular green tea consumption seems to help reduce associated problems of insulin resistance and disrupted glucose and fat metabolism. In a cross-sectional survey of almost five thousand healthy adults in China, between 1-30 cups of green tea per week was associated with lower rates of blood sugar impairment (7). In one systematic review involving almost two thousand subjects green tea was found significantly to lower fasting blood glucose levels (8). In another study, green tea was found significantly to improve measures linked to metabolic syndrome: to decrease weight, BMI (body-mass index), total and low density cholesterol, fat mass, and waist and hip circumference (9).
In a double-blind randomised controlled clinical trial of 60 individuals with raised cholesterol levels 600ml catechin-rich green and oolong tea taken daily for 12 weeks significantly reduced antioxidant enzymes and other measures of oxidative stress, with reductions also in body weight, fat levels and BMI. Markers of fatty liver levels were also improved (10). Green tea was seen in another systematic review of 600 patients with type 2 diabetes, to reduce C-reactive protein levels, one of the classic markers of inflammatory stress (11).
The suggested role of green tea in preventing cancer has been boosted by recent research into mechanisms of action of EGCG (12).
Did you know?
Tea is the most commonly consumed beverage in the world after water, with total annual sales exceeding US$43 billion globally in 2015, more than $11 billion of which is accounted for by green tea.
Green tea, black tea and white tea are all produced from the same plant, Camellia sinensis. Two varieties are widely used as sources of most of the tea around the world, Camellia sinensis var sinensis which is commonly known as Chinese tea and C. sinensis var. assamica or Assam tea. Tea is an evergreen shrub native to East Asia and possibly originating in the borderlands of northern Burma and southern China. It has hybridized over at least 20,000 years and now most original wild varieties have disappeared. It is now mainly cultivated in China, India and Vietnam. It can grow to heights of 17 metres and is a tree in some locations. The leaves are a distinct bright and shiny green with a hairy underside.
The flowers are a creamy white with a light scent and grow in clusters of two or four. The fruits of the tea plant are a brownish-green and can contain up to four seeds. The Chinese variety is considered to be slightly more ‘hardy’ and its leaves are generally smaller and more narrow. It is primarily this variety that is used to produce Green tea.
- Grüner Tee (Ger)
- Thé vert (Fr)
- Tè verde (Ital)
- Té verde (Sp)
- Haree chaay (Hindi)
Moderate consumption of green tea as a beverage is safe and very widespread. There are concerns with taking high doses of green tea extract, with some cases of liver damage reported. Levels of EGCG are accepted as being a useful determinant of safety and this is more concentrated in extracts: a review of toxicological and human safety data suggests a safe intake level of up to 700 mg EGCG/day for adults when green tea is taken as a beverage. The estimated daily intakes of EGCG can reach approximately 560 mg/day if consuming three 8 oz. cups of green tea per day (13).
1-3 teaspoons dried leaf infused in hot (not boiling) water, one to three times a day.
Green tea has similar constituents to the fresh leaf (1):
- Flavanols up to 30% dry weight including catechins (epigallocatechin gallate (EGCG), epicatechin (EC), gallocatechin (GC), epigallocatechin (EGC), epicatechin gallate (ECG), and gallocatechin gallate (GCG)); also chlorogenic acid, coumarylquinic acid, theogallin (3-galloylquinic acid)
- Methylxanthines caffeine (2.5-4.5%), theobromine, theophylline (only traces)
- Amino acids incl. L- theanine (5-nethylglutamine)
According to the United States Department of Agriculture (USDA) brewed green tea contains an average of 126.6 mg total catechins and 77.8 mg EGCG per 100 ml, on the basis of 1 g leaf/100 mL infusion.
Black tea involves the oxidation of the catechins, enzymatically producing various condensation quinone compounds, including thearubigens, bisflavanols, theaflavins, epitheaflavic acids, which impart the characteristic taste and colour properties of black tea, as well as proanthocyanidins. Most of these compounds readily form complexes, including with caffeine. These complexes are erroneously given the name ‘tannins’: in fact there is no tannic acid in black tea.
The catechin EGCG translates its powerful antioxidant properties in the laboratory into real benefits by reducing inflammatory damage in the body (2).
- Rasa (taste) Bitter and astringent.
- Virya (action) Stimulating and cleansing.
- Vipaka (post-digestive effect) Stimulating and cooling.
- Guna (quality) Drying.
- Dosha strengthens vata and pitta, and reduces excessive kapha
- Dhatu (tissue) Cardiovascular.
- Srotas (channel) Cardiovascular, lymphatic, hepatic.
Natural Balance Tea
When our digestive fire is low and our metabolism feels sluggish it cannot transform food into nourishing energy. Instead, food can get stored as fat, starting a vicious cycle where digestion becomes weaker and weaker, leading to steady weight gain. This delicious tea helps to stimulate the metabolism and supports your body to find your natural and balanced weight.
- Cinnamon bark 4g
- Ginger root powder 2g
- Orange peel 2g
- Green tea 2g
- Turmeric root powder 1g
- Black pepper 1g
- Orange essential oil a drop per cup
This will serve 2–3 cups of digestion enhancing, weight-balancing tea that works together with lots of exercise.
- Put all of the ingredients in a pot (except for the orange essential oil).
- Add 500ml (18fl oz) freshly boiled filtered water. Leave to steep for 10–15 minutes, then strain.
- Add one drop of orange essential oil to each cup
- Graham HN (1992) Green tea composition, consumption, and polyphenol chemistry. Preventive Medicine, 21, 3: 334-350
- Kanlaya R, Thongboonkerd V. (2019) Molecular Mechanisms of Epigallocatechin-3-Gallate for Prevention of Chronic Kidney Disease and Renal Fibrosis: Preclinical Evidence. Curr Dev Nutr. 2019;3(9):nzz101
- Mancini E, Beglinger C, Drewe J, et al (2017). Green tea effects on cognition, mood and human brain function: A systematic review. Phytomedicine. 34: 26-37
- Alexopoulos N, Vlachopoulos C, Aznaouridis K, et al. (2008) The acute effect of green tea consumption on endothelial function in healthy individuals. Eur J Cardiovasc Prev Rehabil. 15(3): 300–305
- Lorenz M, Rauhut F, Hofer C, et al. (2017) Tea-induced improvement of endothelial function in humans: No role for epigallocatechin gallate (EGCG). Sci Rep. 7(1): 2279
- Wasilewski R, Ubara EO, Klonizakis M. (2016) Assessing the effects of a short-term green tea intervention in skin microvascular function and oxygen tension in older and younger adults. Microvasc Res. 107:65–71
- Huang H, Guo Q, Qiu C, et al. (2013) Associations of green tea and rock tea consumption with risk of impaired fasting glucose and impaired glucose tolerance in Chinese men and women. PLoS One. 8(11): e79214
- Kondo Y, Goto A, Noma H, et al. (2018) Effects of Coffee and Tea Consumption on Glucose Metabolism: A Systematic Review and Network Meta-Analysis. Nutrients. 11(1): 48
- Payab M, Hasani-Ranjbar S, Shahbal N, et al. (2020) Effect of the herbal medicines in obesity and metabolic syndrome: A systematic review and meta-analysis of clinical trials. Phytother Res. 34(3): 526-545
- Venkatakrishnan K , Chiu HF , Cheng JC , et al. (2018) Comparative studies on the hypolipidemic, antioxidant and hepatoprotective activities of catechin-enriched green and oolong tea in a double-blind clinical trial. Food Funct. 9(2): 1205-1213
- Asbaghi O, Fouladvand F, Gonzalez MJ, et al. (2019) The effect of green tea on C-reactive protein and biomarkers of oxidative stress in patients with type 2 diabetes mellitus: A systematic review and meta-analysis. Complement Ther Med. 46: 210-216
- Almatroodi SA, Almatroudi A, Khan AA, et al. (2020) Potential Therapeutic Targets of Epigallocatechin Gallate (EGCG), the Most Abundant Catechin in Green Tea, and Its Role in the Therapy of Various Types of Cancer. Molecules. 25(14): E3146
- Hu J, Webster D, Cao J, Shao A. (2018) The safety of green tea and green tea extract consumption in adults – Results of a systematic review. Regul Toxicol Pharmacol. 95: 412-433